Beluga Whale: Characteristics, Habitat and Behavior

Written and verified by the biologist Cesar Paul Gonzalez Gonzalez

Last update: 30 June, 2023

The beluga whale – also known as the white whale – are beautiful marine animals that are characterized by having a rather prominent “head”. They’re close relatives of dolphins, so their morphology is quite similar. However, they’re fully adapted to the cold and live in areas that aren’t suitable for other species.

The scientific name of this “whale” is Delphinapterus leucas. It belongs to the order Cetacea, in which all aquatic mammals are grouped. Read on to discover everything you need to know about the beluga whale.

Beluga whale taxonomy

The beluga whale is part of the odontocetes (Odontoceti), a group of marine mammals characterized by having teeth in their mouths. According to a study published in the journal Conservation Genetics Resources, its closest relatives are narwhals and dolphins, with which it shares much of its morphology. Even so, their aspects differ enough to distinguish each one easily enough.

This beautiful species is the only one of its genus (Delphinapterus), although some recent analyses suggest that there are several subpopulations that could diversify its lineage. According to the International Union for Conservation of Nature (IUCN), at least 21 isolated populations are known to exist in partial isolation throughout its range.

This means that although there’s only one species within the genus, subpopulations could develop into subspecies if conditions are right. This is still an assumption, because at the moment there’s no hard evidence to support it. However, it’s well known that geographic isolation is a decisive factor in speciation.

Where does this marine mammal live?

Beluga whales live in the waters of the Arctic and sub-Arctic regions. In fact, they’re one of the few marine mammals that remain year-round in this area. In this regard, a study in the journal Polar Biology argues that the species is closely associated with sea ice.

These small “white whales” spend most of their time near the shore or ice formations, but are capable of entering the ocean or diving to depths of nearly 800 meters (half a mile).

However, observations of the species seem to indicate that the cold has some restrictive effect on its movements, as when temperatures drop it tends to stay close to the surface.

Physical characteristics of the beluga whale

The beluga whale is called the “white whale” because, as an adult, it exhibits a distinctive white color throughout its whole body. In addition, it measures between 3 and 7 meters (around 10 to 23 feet) in length, which rivals the size of the pygmy right whale.

This marine mammal also demonstrates sexual dimorphism, with respect to its size. According to the Animal Diversity Web, males of the species are about 25% larger than the females.

Looked at another way, there’s an average difference of 1.2 meters (4 feet) in length between the two sexes.

Although it’s known as a “whale”, its morphology is more similar to that of a dolphin. However, it’s characterized by two main differences: it doesn’t have a dorsal fin and its head has a protuberance, due to the organ known as a “melon”. This organ is essential for the beluga whale, as some specialists suggest that it serves as a support for the echolocation system.

In summary, the beluga whale’s body is elongated and curved, with a prominent “hump”. In addition, it has two pectoral fins and a caudal fin. Its skin is thick and may appear smooth or have a series of folds or wrinkles. It also has a relatively “small” mouth with a series of 8 to 9 teeth in each jaw.

Appearance of hatchlings

Beluga whale hatchlings maintain the same physical characteristics as adults, with the exception of the white color typical of the species. At birth, the young exhibit shades of gray, brown, or dark blue, which lighten as they grow to white. However, at this point in their life they can be confused with their close relatives: narwhals.

The beluga whale is a carnivorous animal that feeds on a wide variety of fish and marine invertebrates. Due to its distribution, its diet may vary somewhat depending on the availability of prey in its habitat. Even so, the most common components of its diet are the following:

• Octopus
• Squid
• Shrimp
• Salmon
• Arctic cod
• Eulachon (also called the candlefish)
• Rainbow smelt

According to a study published in the journal Marine Fisheries Review, the diet of beluga whales also changes as they grow older. Juveniles tend to consume small prey such as crabs and shrimp, while adults seek larger snacks.

Contrary to what one might think, beluga whales eat their prey whole or in large chunks. Although they have teeth, these aren’t as long and make crushing difficult. This is the main reason why they prefer to swallow their food rather than chew it.

Beluga whale behavior

This species has a calm and serene behavior, and spends most of its life swimming slowly throughout its habitat. Unlike other “whales,” beluga whales don’t tend to jump or leave the water frequently.

However, every so often they need to come to the surface to breathe, but they only need to expose their blowhole – their breathing orifice – to supply their oxygen demand.

During the winter season, some beluga whale populations choose to migrate to warmer areas in the subarctic regions.

Regarding this displacement, a study in the journal Polar Biology, published in 2014, mentions that it seems to be an adaptation to the lack of seasonal resources. Similarly, there’s some fidelity for their breeding sites.

Another interesting aspect is that beluga whales follow the same migratory route as their predecessors. This means that their movements can be predicted. In view of this, hunters and some predators take advantage of this behavioral trait to capture them.

This marine mammal is a social species that enjoys living in groups of 2 to 10 members. In times of migration, this number may momentarily increase too much. However, this depends very much on the population density of the area.

Vocalizations

Beluga whale vocalizations are somewhat similar to those of dolphins. However, the patterns and intensity are different, so much so that they seem to be governed by a complex and unknown “language”. According to a study published in The Journal of the Acoustical Society of America, it has been detected that they have at least 34 different types of vocalizations.

Although it’s still too early to say what each of these sounds means, it has been shown that they’re used in certain predetermined patterns. As mentioned in a study reported in the journal Marine Biology, beluga whales have special vocalizations for long and short-distance communication.

Reproduction

Beluga whale reproduction takes place before the winter migration, so it has an interval that lasts from spring to autumn. The goal is for females to have their offspring in areas with “warm” waters and abundant resources.

Beluga whales are polygamous and both females and males mate with several partners. In fact, according to an article published in the journal Aquatic Mammals, there’s sperm competition in the species. This means that the male that fertilizes the female is the one that produces the “fittest” and fastest sperm, which serves as a force of natural selection.

Beluga whale gestation lasts approximately 14 months and gives birth to a single calf. Once born, the young is dependent on its mother for at least 2 years. This is one of the reasons why it only has one calf every 3 years.

Conservation status

The International Union for Conservation of Nature (IUCN) classifies the beluga whale as a species of “Least Concern”. This is due to the lack of information on its population. Because of this, it’s impossible to assign it a risk level according to its status.

However, different local governments – such as Alaska- have reported an alarming decrease in the number of beluga whales near their coasts. As a result, some countries classify the species as “threatened” or “at risk”. Although it doesn’t have many predators, it faces other dangers, such as hunting, pollution of its habitat, and climate change.

Enigmatic marine mammals

As can be seen, beluga whales are interesting animals that harbor several curiosities. Although many aspects about them are unknown, it’s clear that they’re striking animals of great economic and biological importance.